Orthopaedics Flashcards
What are stressors of the musculoskeletal system
Trauma
- Sports injuries
- RTA’s
- Overuse
Infection
- Bone and joint
Altered metabolism
- Age related
- Disease related
Neurological
- Muscle spasticity
- Muscle paralysis
what joints can be replaced
All joints
- Upper limb: shoulder / elbow / wrist / hand
- Lower limb: hip / knee / ankle
- Spine: disc replacements
what are the indications for joint replacement
Degenerative disease (e.g. osteoarthritis)
Inflammatory disease (e.g. rheumatoid arthritis)
Trauma (e.g. fracture neck of femur / fracture neck of humerus)
Tumour
Vascular disease (e.g. Avascular necrosis)
Revision of previously failed / worn out joint replacement
what are the three types of joint replacement
cemented
hybrid - cemented stem but acetabulum is uncemented
reverse hybrid - uncemented stem and cemented cup
uncemented
uncemented is more…
expensive but is now more common
how long do joints last
15-20 years
- depends on type of replacement
- type of materials used
what is one of the most common surgical proceeder today
total hip replacement
some joints will always require …
cemented
name a difference between cemented and uncemented
- Cemented = can get the person mobile the next day
- uncemented.=. have to wait for the bone to grow into the porous part of the replacement joint therefore takes 4-6 weeks of non weight bearing on that joint
who is cemented better for
- obese
- elderly
- people with osteoporosis
what polymer is in cemented replacements
Cemented fixation uses an acrylic polymer
Poly(methyl methacrylate) (PMMA)
- can give prophylactic antibiotics to prevent infections
described cemented placement
- both the bone and cement must lock together to make the insertion last
- cement simply acts as a filler between the bone and the implant
describe the uncemented replacement
Uncemented have rough surface covered with porous or hydroxyapatite covering
Maximum bone ingrowth is obtained with pore size 100-200 μm
Gap should be <0.5mm to encourage bone growth
describe the benefit of using ceramic on ceramic as a new biomaterial
- has least wear
- less than 1 um a year -
- fewer infections
- more inert and less likely to start an immune reaction therefore less chance of aseptic loosening
- but small rate of catastrophic failure - over stress ceramic can cause it to collapse
describe other biomaterials that can be used
ceramic on ceramic
Metal on metal
Ceramic in cross-linked polyethylene
Oxinium in cross-linked polyethylene
Metal in cross-linked polyethylene
- 200μm a year
- can lead to aseptic loosening
(listed in the wear and tear rate)
what joint has the least wear rate
ceramic on ceramic
what is the indicators for spinal decompression surgery
Spinal stenosis
Damaged IV disc
Fractured vertebrae
Tumours
what is spinal fusion and what is it for
Where 2 or more vertebrae are joined together with a section of bone to stabilise and strengthen the vertebral column
- won’t affect the movement of the vertebral column as the movement between two vertebra is quite small
What can you use for spinal decompression surgery
bone graft
spinal fusion
IV disc replacement - allow rotational movement
inject bone cement in the centre of the vertebral body that will harden the vertebra
what soft tissue treatments are there
Tendon repair
Tendon transfer
Tendon lengthening
Ligament repair
Ligament replacement
Free muscle transfer
what are the options for tendon transfer for radial nerve palsy
- PT to ECRB for wrist extension
- FCU to EDC for finger MCP extension
- PL to rerouted EPL for thumb extension
Or - PT to ECRL and ECRB
- FDS III to EDC
- FDS IV to extensor indicis and EPL
- FCR to APL and EPB
what is tendon lenghting for
- this is where you have hypertonia in muscle groups
for example - For the lower limb one of the antagonist groups of muscles that are stronger than the other for example the quads are stronger than the hamstring and plantarflexors are stronger than dorsiflexors
Hypertonic plantarflexors – end up toe walking, dorsiflexors cannot counteract it
what can you use for ACL reconstructions
patellar ligament tibia graft,
- goes down from the patellar down the patella ligament to the tibia tuberosity where it inserts, this is meant to heal in quicker as it is bone
- tends to heal quicker
Hamstring
- semitendinous overlies semimembranous therefore you can stitch the muscle to semimebranous underneath it and take the tendon part of semitendinous and use it for the ACL
- gracilis tendon
What is the unhappy triad
Medical mescius
ACL
Medial collateral ligament
what are free muscle transfer
can use gracilis muscle and rectus femurs
what muscles are used in free muscle transfer
- gracilis or rectus femoris
- or any muscle that is expendable (other muscles do its role)
- under voluntary control
- is superficial
what can the gracilis muscle be used for
Deltoid reconstruction
Elbow flexion
Elbow extension
Finger flexion
Finger extension
what is mal union
bone has healed but there is Misalignment of proximal and distal fragments leading to biomechanical deformity
what can mal union lead to
Rotation
Angulation
Shortening
Translation
what is delayed
Failure to consolidate within 1.5x the normal expected time
What is non union
Failure to consolidate within 2x the normal expected time
what happens in non union
Can be Atrophic / Hypertrophic depending on:
- blood supply
- degree of stability
what can be used to treat a mal union
Osteotomy
- Re-alignment osteotomy
What can be used to treat a shortened bone
- Distraction osteogenesis
- progression correctvtion with use of an external fixator (e.g. Ilizarov technique)
name 4 types of bone graft
Osteogensis
osteoconduction
osteoinduction
osteopromotion
what is osteogenesis
Formation or development of new bone cells contained in graft
what is osteoconduction
Physical effect by which the matrix of the graft forms a scaffold that favours outside cells to penetrate the graft and form new bone
what is osteoinduction
Chemical process by which molecules contained in the graft convert the neighbouring cells into osteoblast
what is osteopromotion
When the grafted material enhances osteoinduction
define autograft
a tissue or organ that isgraftedinto a new position on the body of the individual from which it was removed.
define allografts
a tissue or organ obtained from one member of a species andgraftedto a genetically dissimilar member of the same species.
define xenografts
agraftobtained from a member of one species and transplanted to a member of another species.
define alloplast
an inert foreign body used for transplantation into tissues.
what rehabilitation takes place after orthopaedic surgery
Orthopaedic Physiotherapy
- specialises in treating patients undergoing planned surgery
- or those who are admitted to hospital due to a traumatic accident or incident
